Method of treating hides or skins.



UNITE STATES Patented May 12, 1903.

ARNOLD H. PETER, OF NEW YORK, N. Y.

METHOD OF TREATING HIDES OR SKINS.

SPECIFICATION forming part of Letters Patent No. 727,832, dated May 12, 1903.

Application filed October 18,1902. Serial No. 127,790. (No specimens.)

To atZZ whom it may concern:

Be it known that I, ARNOLD H. PETER, a citizen of the Republic of Switzerland, residing in the city, county, and State of New York, haveinvented a new and useful Improvement in Methods of Treating Hides or Skins before Their Subsequent Immersion into a Tanning- Bath, and my process can be used with all kinds of hides and skins, and such hides or skins after treatment by my process may be tanned in either organic or metallic tanningbaths.

The object of my invention has been to dispense with and replace the costly, hazardous, and heretofore-considered indispensable processes known as hating, abating, grainering, reducing, degreasing, drenching, and puring. (See Davis, The Manufeature of Leather.)

By these operations above described I refer to all operations ordinarily performed on the hide or skin subsequent to the removal of the hair by liming and previous to the immersion of the hide or skin in the actual tanningbath except washing and the mechanical operation of fleshing or slating.

My invention consists in the discovery that hides and skins coming from the lime after undergoing the usual Washing and the me-' chanical operation of fieshing can be put into suitable condition for immersion in the tanning liquor without resorting to bating, abating, grainering, reducing, drenching, or puring, as is now commonly employed.

The elimination of the lime or alkali, thement with a suitable acid and salt solution,

applied as hereinafter specified. After treatment according to my process the acid and salt solution remaining in the hide can act upon it practically by what is known as horsing the hides. A perceptible change in the hide or skin will be noticed during the next twelve to forty-eight hours, and in this state the hides or skins may be kept for a number of days without injury and ready for immersion in the actual tanning-bath. At the first glance at this state of the hides or skins they may appear somewhat similar to that presented byimmersing them in an ordinary pickle; but the differences are very marked in the quality of the skin or hide before immersion in the tanning liquor, and I obtain this difference by the relative quantities of the salt and acid used in my process, which differ both in quantity and method of application from those heretofore used.

The following will serve as an illustration of a method of applying my process of treating the hides or skins with a suitable salt and acid solution for the purposes specified.

The hides or skins (after being taken from the lime and being unhaired, washed, and fleshed in the usual manner) are placed in an aqueous solution containing from one to five per cent.'of chlorid of sodium and one tenth of one per cent. of commercial muriatic acid, (HOL.) After a period of from one to two hours it will be found that almost all acid reaction has disappeared, and at this time another one-tenth of one per cent. of muriatic acid is to be added. After a further period of from one to two hours the acid reaction becomes very weak, and thus again onetenth of one per cent. of muriatic acid is to v from superfluous liquor by mechanical means,

such as beating or working, or the superfluity may even be removed by washing. Again, the amounts of acid may be changed somewhat and instead of muriatic acid I can employ sulfuric acid (H 80 or phosphoric acid (PO H or lactic acid, (G H,O Still, again,the timeof the intervals between adding each dose of the acid may vary and the temper- ICO ature at which the operations are performed may vary. In my tests I have found that the treatment can be carried on successfully at a degree of temperature as low 23 centigrade and again as high as 40 centigrade, the degree of temperature being determined by the nature of the hides or skins and the effect on the grain, as different skins act differently under the same treatment. Thus the softer natured skins, such as those of sheep and colts, require a lower temperature, and the harder skins, such as those of goats, permitting a higher temperature. The test, as is understood by practical tanners, is to be determined by the feel of the grain, whether it is smooth or not and general appearances.

I do not confine myself to solutions specifically containing from one to five percent. of salt, as I have successfully used solutions containing up to twelve per cent. of salt and again down below one per cent. of salt.

My invention consists in the use of an acid and a salt solution for the treatment of hides or skins coming directly from the lime and previous to immersion in the tanning liquor, in which the acid is used in such quantities and qualities only at the time that it is used that the acid will act to combine with the lime, but will not combine to any extent with the substance of the hides. The affinity between the lime and the acid being greater than between the hide substance and the acid, my treatment renders it possible to remove the lime without causing the acid to combine with the hide substance to any large extent, and thus leave the hide in its natural condition. The salt is to be used in such quantities only as to overcome the swelling action of the acid on the skins or hides, and it is also used for the purpose of preventing a toorapid action of the acid. The acid react-ion depends or appears to depend on the electrolytical disassociation of the acid employed, and the presence of a salt of the acid reduces or modifies this electrolytical disassociation, and thereby reduces the rapid action of the acid.

A further important part of my process consists in the discovery that the specific gravity (to be regulated by the amount of salt to be used in the solution) in which the hides or skins are to be immersed under my process before treatment with the tanning solution should be substantially the same as the specific gravity of the tanning-bath. By having these specific gravities coincide or nearly coincide I have discovered that there is little or no formation of strong currents of dilfutexture of the hides, and consequently upon the ultimate texture of the leather produced therefrom.

I have discovered that the treatment of hides and skins in the manner above described results in a fuller stronger leather of better grain and fiber and produced at a less expense than by the processes heretofore used for similar purposes.

Having thus described my invention, What I claim is 1. In tanning hides or skins, the process of subjecting the hide or skin to the action of a solution of a salt into which relatively small quantities of an acid are introduced at intervals, substantially as and for the purpose set forth.

2. In tanning hides orskins, the process of subjecting the hide or skin to the action of a solution of sodium chlorid into which relatively small quantities of acid are introduced at intervals, substantially as and for the purpose set forth.

3. In tanning hides or skins, the process of subjecting the hides or skins to the action of an aqueous solution of sodium chlorid into which relatively small quantities of hydrochloric acid are introduced at intervals, substantially as and for the purpose set forth.

4. In tanning hides or skins, the process of subjecting the hide or skin to the action of a solution of sodium chlorid into which acid is introduced at intervals, and subsequently subjecting the hides or skins to the action of a tanning-bath having substantially the same specific gravity as that of the salt and acid bath, substantially as and for the purpose set forth.

5. In tanning hides or skins, the process of subjecting the hide or skin to the action of a solution of sodium chlorid into which relatively small quantities of acid at intervals are introduced, and subsequently subjecting the hides or skins to the action of a tanning-bath having substantially the same specific gravity as that of the salt and acid bath, substantially as and for the purpose set forth.

6. In tanning hides or skins, the process of subjecting the hide or skin to the action of an aqueous solution of sodium chlorid into which relatively small quantities of hydrochloric acid are introduced at intervals, and subsequently subjecting the hides or skins to the action of a tanningbath having substan tially the same specific gravity as that of the salt and acid bath, substantially as and for the purpose set forth.

ARNOLD II. PETER.

Witnesses:

MATTHEW W. W001), J. E. I'IINDON HYDE. 

